Flexible tube forming machine



July 29, 1969 c. w. SMOLA 3,457,749

1 FLEXIBLE TUBE FORMING MACHINE Filed June 8, 1966 2 Sheets-Sheet 1 FIGSFlGZ) INVENTOR CARL 1/24 SMOLA ATTORNEYS y 1969 c. w. SMOLA 3,457,749

FLEXIBLE TUBE FORMING MACHINE Filed June 8, 1966 2 Sheets-Sheet FIG. 9

INVENTOR CARL W SMOL A- ATTORNEYS United States Patent 3,457,749FLEXIBLE TUBE FORMING MACIHNE Carl W. Smola, Detroit, Mich, assignor toVersatube C0rp., Detroit, Mich, a corporation of Michigan Filed June 8,1966, Ser. No. 556,075 Int. Cl. B210 37/12; 1321f 3/04 U.S. Cl. 7250 3Claims ABSTRACT (IF THE DISCLOSURE This invention relates to machinesfor forming hollow tubing and more particularly to a machine forproducing an improved, sealed flexible tubing spirally wound from acontinuous strip of metal.

Flexible tubing of the character to which the machine of the presentinvention relates is adapted to a wide variety of uses such as exhausttubing for automotive and aircraft vehicles, conduits for electricalwiring, heating and cooling coils and the like.

The properties that are most desirable in tubing of this type is that itbe flexible under severe service while maintaining fluid or gas tightcharacteristics. It is the broad purpose of the present invention toprovide tube forming apparatus adapted to develop a flexible tubingwhich will maintain its sealed, fluid tight properties under theseverest of service.

conventionally, flexible tubing is produced by feeding a continuous flatstrip of a suitable material through successive pairs of profilingrolls. The profiling rolls countour the strip so that it emerges fromthe final pair of rolls with a generally S-shaped cross-section havingactutely bent oppositely turned flanges. The flanged strip is thendelivered tangentially to the peripheral edge of an elongated rotatingmandrel. A die cooperates with the mandrel to coil the flanged striparound the mandrel such that flanges of the adjacent edges of the stripare brought into engagement. A pressure roll then exerts a force on theengaged flanges to cause them to collapse against the mandrel such thatthe inner surface of the produced tubing assumes the configuration ofthe circumferential surface of the mandrel.

It is the broad purpose of the present invention to improve the fluidtight characteristics of spirally wound flexible tubing by providing aset of profiling rolls having peripheral edges which are adapted to takethe strip, between them and which cooperates to form a longitudinalgroove adjacent one edge of the strip. Preferably the groove is formedprior to the flanging steps and is provided in the portion of the stripforming one of the flanges.

A strip of sealing material is inserted in the groove subsequent to theprofiling operation, but prior to the coiling step. The sealing materialis chosen to suit the purpose for which the finished tubing is to beutilized, but for purposes of description may be a copper or bronze wireor an asbestos thread.

During the coiling step, the pressure rolls collapse the flanges againstthe mandrel such that the sealing strip is tightly contained between thegrooved flange and the body of the strip. Thus the improved tubingretains its sealed shape even as the flanges are worked against one iceanother such as when subjected to severe and continuous vibrations.

Another feature of the improved tube forming machine, takes the form ofa die shoe which is provided with a pair of parallel slots running inthe direction of the moving strip and which positively contains theflanged strip against lateral movement as it assumes a coiled shapearound the rotating mandrel. The double slotted die cooperates with themandrel to ensure that the flanged convolutions of the strip are fullyengaged and prevent twisting of the strip that may result in the flangesslipping out of engagement before they have been securely interlocked bythe pressure rolls.

It is therefore an object of the present invention to provide spiraltube making machines adapted to produce an improved fluid tight flexibletubing by providing a pair of profiling rolls which cooperate to form alongitudinal groove in the strip forming the tube and which groove isadapted to retain a sealing material in the finished tubing.

It is another object of the present invention to improve flexible spiraltube forming machines by providing a die associated with a rotatingmandrel having a pair of parallel slots running in the direction of theadvancing flanged strip and which slots prevent lateral movement of thestrip as the flanges of adjacent coiled strips are engaging one another.

Other objects, advantages and applications of the present invention willbecome apparent to one skilled in the art to which the inventionpertains upon reference to the following detailed description of thepreferred embodiment of the invention and to the accompanying drawingsin which like reference characters refer to like parts throughout theseveral views, and in which:

FIGURE 1 is a schematic elevational view of a hollow tube formingmachine illustrating a preferred embodiment of the present invent-ion;

FIGURE 2 is a sectional view taken through a first pair of profile rollsillustrated in FIGURE 1 and as seen from line 2-2 of FIGURE 1;

FIGURE 3 is a fragmentary sectional view as seen from line 3-3 of FIGURE1;

FIGURE 4 is a fragmentary view as seen from line 4-4 of FIGURE 1;

FIGURE 5 is a fragmentary view as seen from line 5-5 of FIGURE 1;

FIGURE 6 is a sectional view of a strip guide trough as seen from line6-6 of FIGURE 1;

FIGURE 7 is a schematic plan view of the preferred tube forming machineillustrated in FIGURE 1;

FIGURE 8 is a sectional view of the die and mandrel as seen from line8-8 of FIGURE 1;

And FIGURE 9 is a view of a preferred locking configuration for amandrel and its associated drive shaft.

Referring to FIGURES l and 7 a preferred spiral tube making machinecomprises a motor 10 drivingly connected to a profiling assemblygenerally indicated at 12 and a coiling assembly generally indicated at14 all of which are mounted on a base member 16.

The profiling assembly 12 preferably comprises four pairs of alignedprofiling rolls 18, 20 and 22 and 24 rotatably mounted in a gear box 26which is fixed to the upper surface of the base 16. The motor 10 hasoutput through a sprocket assembly 28 to a gear box 30 which isoperatively coupled with the input of a gear box 26 through thecoupling.

The profiling rolls 18, 20, 22, and 24 are preferably mounted to thegear box 30 such that a continuous strip 32 of a suitable metallic tubeforming material such as aluminum, stainless steel, or the like isadvanced successively through each pair of profiling rolls in a linearpath. The strip 32 first passes between the profile rolls 18 each ofwhich has a peripheral surface which mate with one another as can beseen in FIGURE 2 to form a longitudinal grooved section indicated at 34and which preferably formed adjacent one edge of the strip 32.

The strip 32 then is delivered from the profile rolls 18 to the secondpair of profile rolls 20 which as can be seen in FIGURE 3 have matingperipheral surfaces which cooperate to form a stepped contour or shape36 in the strip 32 approximately intermediate the side edges of thestrip 32. Preferably the half of the strip containing the groove 34 isstepped such that the groove faces away from the other or non-groovedhalf.

The strip 32 is delivered from the profile rolls 20 to the profile rolls22 which as can be seen in FIGURE 4 have mating peripheral surfacesadapted to form oppositely extending flanges 38 and 40 in the strip 32.The flanges 38 and 40 are formed in opposite sides and extend normallyto the body of the strip in opposite directions. The strip 32 thenpasses from the profile rolls 22 and is delivered to the last set ofprofile rolls 24 which cooperate to bend the flanges 38 and 49 inwardlyapproximately 20 to 30 with respect to the body of the strip as can beseen in FIGURE 5. Thus it can be seen that the profile assembly shapesthe flat strip of metal 32 into a generally S-shaped cross-sectionhaving a groove in one of the flanges.

The profiled strip 32 then passes from the profiling assembly 12 to anelongated enclosed guide trough 42 which delivers the contoured strip 32tangentially to the surface to an elongated mandrel 44 rotatably mountedon a frame 46 fixed to the upper surface of base 16. The strip 32 isdelivered at an oblique angle with respect to the axis of the mandrel44. The guide trough 42, as can be seen in FIGURE 1, is carried by aright angle bracket 47 which is fixed to the frame 46. As can be seen inFIGURE 6 a cross-section to the feed trough 42 shows that it has ashaped passage adapted to conform to the generally S-shaped contour ofthe strip 32.

Intermediate the inlet of the trough 42 and the last set of profilerolls 24, a flexible packing 48 is delivered from a spool (not shown) tothe moving flanged strip 32 and fitted into the channel section 34 at apoint immediately adjacent the inlet of the feed trough 42 as can beseen in FIGURES 1 and 6.

The rotary mandrel 44 is carried by a drive shaft 50 which is journalledin the frame 46 and driven by a gear set 52 (FIGURE 7) which isoperatively connected by sprocket set 54 to the output shaft 55 ofreduction gear box 30.

It is to be understood that the peripheral surface of the rotary mandrel44 may take any desired configuration but for purposes of thedescription is shown with a cylindrical surface. It is to be furtherunderstood that the diameter of the mandrel is chosen according to thesize of the tubing that is desired. The mandrel 44 is connected to thedrive shaft 50, as can be seen in FIGURE 9, and the drive shaft 50 hasan axial concentric bore 56 formed on its driving end which carries atransversely extending finger 58 spaced from the open end thereof. Themandrel 44 has a narrowed end which is complementarily shaped to thebore 56 and has substantially the same length as the depth of the bore.A longitudinal slot 62 is formed in the end of the narrowed portion adistance equal to the spacing of the finger 58 from the dead end of the'bore 56. The slot 62 terminates at a short transversely formed slot 64.Thus the Lmandrel 44 is engaged with the drive shaft 50 by inserting thenarrowed end within the bore 56 so that the finger 58 is received by theslot 62, moving the mandrel 44 toward the drive shaft 50 and thenrotating the two such that they become locked together as the finger 58moves within the slot 64.

Three bearing blocks 66, 68, and 70 (FIGURE 7) are carried by the frame46 preferably equiangularly about a short shaft 76. A roller 78 isrotatably carried by each' of the shafts 76.

The shafts 76 are each connected by a universal joint 79 (FIGURE 7) to alink 80 which is rotatably driven by gear set 52 such that the rollers78 have a peripheral surface speed conforming to the surface speed ofthe rotary mandrel 44.

The strip 32 is delivered between the mandrel 44 and the first drivenroller 78 such that it is introduced to a die 82 as can best be seen inFIGURES 1 and 8. The die 82 is adjustably carried by the frame 46 andhas a working surface 84 spaced from the rotating circumferentialsurface of the mandrel slightly greater than the thickness to the strip32. A pair of parallel slots 86 and 88 project normally inward from thesurface 84 to a depth approximately equal to the developed thickness offlanges 38 and 40 and are disposed in the path of the advancing flangedstrip 32. The die cooperates with the mandrel to wind the strip 32spirally on the mandrel such that the trailing flange edge 38 engageswith the leading flanged edge 40 in the die 82. The engaged flangededges advance to the second and third rollers 78 which apply a forcesuflicient to collapse the flanges against the mandrel. The collapsedflanges thus are interlocked together. Referring to FIGURE 8, thesealing strip 48 is trapped in the groove 34 by the body of the stripsuch that it forms a sealing engagement between adjacent coils. Thesealing strip thus permits the interlocked flanges to move relative toone another so that the produced tube may be bent into any desirableshape while ensuring that the tube retains its fluid tight properties.

As the spiral tube develops, it moves progressively away from the die 82and the driven rolls 78 as can be seen in FIGURE 7 where it may bedelivered to a suitable pick-up or coiling means (not shown).

In summary I have described an improved spiral tube forming machineincluding a pair of profiling rollers adapted to provide a longitudinalrunning groove adjacent one end of the uncoiled tube forming stripstock. The groove is adapted to seat a packing or sealing strip which islocked in the groove during the spiral forming process. The lockedsealing strip ensures a fluid tight flexible tubing under extremeworking conditions.

Furthermore, I have described an improved coil forming die adapted topositively retain adjacent sections of the flanged strip as they engageone another and then advance to a pressure roll wherein they areinterlocked.

Although I have described but one preferred embodiment of my invention,it will be apparent to one skilled in the art to which the inventionpertains that various changes and modifications may be made thereinwithout departing from the spirit of the invention as expressed in thescope of the appended claims.

What is claimed is:

1. Apparatus for forming a thin flat strip of continuously fed materialinto a continuous closed spirally wound tubing, comprising:

(a) a frame;

(b) means for bending the edges of the strip material to form flangesextending in opposite directions from the body of the strip, said meanscomprising a plurality of pairs of rolls disposed with their axesparallel to one another and rotatably supported with respect to theframe so that said strip may successively .pass through said rolls, thefirst of the pair of rolls through which said strip is passed havingsuch a configuration as to form a groove adjacent to one end of thestrip and the successive rolls being operative to form said flanges,with said groove being disposed at the extremity of and on the outwardlyfacing surfaces of one of said flanges;

(c) means for introducing a strip of sealing material into said groove;

(d) a mandrel rotatably mounted on said frame;

(e) means for rotating said mandrel;

(f) means for advancing the flanged strip material tangentially to saidrotating mandrel and in a direction oblique to the axis of the mandrelwhile maintaining said sealing strip Wihtin said groove;

(g) a die fixed to said frame and presenting a working surface closelyadjacent the circumferential surface of said mandrel, and said dieeffective to produce a helical form to the strip to assist in coiling itin helical convolutions on the rotating mandrel and with said slotscooperating to engage the flanges of adjacent convolutions; and

(h) roll means disposed in the path of the advancing engaged flanges andoperable to sealingly collapse said flanges against the body of saidstrip material with the surface of the flange containing said groovebeing collapsed against the body of said strip material whereby saidsealing strip is pressed directly against said body of said stripmaterial to produce a seal between said flange and the body of saidstrip material.

2. The invention as defined in claim 1, wherein said last mentionedmeans comprise:

(a) a plurality of rolls connected to said frame for adjustable movementtoward and away from the longitudinal axis of said rotating mandrel,said rolls disposed in the path of the engaged flanged strips;

(b) means for rotating said rolls in timed relationship to said rotatingmandrel; and

(c) said rolls having a smooth peripheral surface for collapsing saidengaged flanges into interlocking relationship.

3. The invention as defined in claim 2, wherein said slotted die isdisposed to receive said advancing strip substantially at the point oftangency between the advancing strip and the surface of the mandrel.

References Cited UNITED STATES PATENTS 1,580,760 4/1926 Palmer 72-502,595,747 5/1952 Anderson 7250 2,686,487 8/1954 Carr 725O CHARLES W.LANHAM, Primary Examiner ANDREW L. HAVIS, Assistant Examiner US. Cl.X.R. 72142

